1. Field of the Invention
The present invention relates to a pup joint and, more particularly, to a pup joint which includes means for maintaining the wing nut and retainer segments in a position adjacent the male sub at all times.
2. Description of Related Art
Pup joints are relatively small lengths of pipe used in the oilfield industry to conduct fluids from one piece of equipment to another. Typical pup joints comprise a length of pipe having a male sub located at one end, a female sub located at the other end and a wing nut for connecting the male end of one pup joint to the female end of another pup joint. The male sub includes a spherical sealing surface, and the female sub includes a mating conical scaling surface and a set of external threads. The wing nut is retained on the pup joint by means of a shoulder or a set of retainer segments and engages the threads of the female sub to secure two pup joins together.
Maintaining the wing nut and retainer segments adjacent the male sub end has been somewhat of a challenge in prior art pup joints. In certain prior art pup joints constructed of heavy-wall tubing, the wing nut and retainer segments are held in place by means of an interference fit with the male sub tubing. In lighter weight pup joints, however, this interference fit does not exist. Therefore, when a pup joint is held in a non-horizontal position, the wing nut is permitted to slide down the pup joint, thus creating difficulties during installation.